Device for printing fabrics made of vegetable fibers from a web of transfer paper

ABSTRACT

The web of fabric (9) passes over an input roll (10) arranged substantially at the level of the upper portion of the heating drum (1), around at least half the circumference of which it winds after coming into contact with a web of transfer paper (14). The drum and the pressing roll (2) between which the webs pass are received inside one and the same closed housing (3) swept by air that becomes laden with the vapors of the transport agent, the laden air being delivered to a tank of cold water (22). The apparatus finds use in the printing of fabrics made of vegetable fibers, in particular cotton.

BACKGROUND OF THE INVENTION

The invention relates to the printing of colours or patterns from a webof transfer paper and, more particularly, to a device for transfer to afabric made of vegetable fibers.

A device for transfer from papers having sublimable inks thereonperforms the function of placing a web of paper in contact on a web offabric by imparting thereto a moderate pressure, in such a way that thepattern and the colours on the paper are transferred to the fabric. Forthis purpose, the paper comprises, in addition to the colouring agents,a transport agent which melts through the effect of heat and whichdissolves the colouring agents and then entrains them into the fiber ofthe fabric.

However, this transport agent has the major drawback of causing asubstantial release of very dense vapors during the transfer phase,which is carried out at around 200° C.; these vapors then recondense atthe time of cooling and form large deposits on the surrounding floor andon the transfer machine, which represents an unacceptable inconvenience.

Transfer to a fabric made of vegetable fibers, for example cotton, thusappears to be impossible using the conventional sublimation technique.

To avoid this drawback associated with the necessary presence of thistransport agent, the inventor has devoted his attention to thedevelopment of a device which associates with the transfer operation,properly speaking a complementary operation, involving the extraction ofthe transport agent, which thus makes it possible, without detriment tothe environment, to effect transfer onto a fabric made of vegetablefibers.

SUMMARY OF THE INVENTION

A main object of the present invention thus resides in a device forprinting a fabric made of vegetable fibers from a web of transfer paperbearing coloring agents and a transport agent, comprising a heatingcalendering drum and a pressing roll between which a web of fabric and aweb of transfer paper supplied by independent payout rolls, come intocontact with one another, a device in which the web of printed fabricremains in contact with the heating drum over at least half itscircumference, the said heating drum and the pressing roll beingreceived inside one and the same housing swept by air, which becomesladen with the vapors of the transport agent, the laden air being sentto a tank of cold water.

To permit this contact, the web of fabric passes over an input roll,arranged substantially at the level of the upper portion of the drum,before penetrating the enclosure and passes back over a guide roll, alsooutside the enclosure and arranged in the vicinity of the input roll,above the level of the lower portion of the drum.

According to one alternative form of embodiment, the transfer paperremains pressed against the fabric over a certain portion of the heatingdrum, beyond the point of contact with the pressing roll, and passesback over an idler roll.

To ensure air circulation, the closed housing is provided, at its lowerportion, with air inlet openings and, at its upper portion, with adischarge tube, equipped with an extraction means, emerging in the tank.

Further characteristics and advantages of the invention will be moreclearly perceived upon reading the following description of anon-limitative example of embodiment referring to the sole FIGUREannexed.

BRIEF DESCRIPTION OF THE DRAWING FIGURE

The single FIGURE of the drawing, FIG. 1, is a schematic elevationalview of a printing device according to the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

FIG. 1 shows a calendar in the form of a heating drum 1 onto which apressing roll 2 comes to bear from above. The whole is received in aclosed housing 3 accessible via an entry 4 in the form of a hinged door.Outside the housing are provided a transfer paper payout roll 5 and aroll 6 for recovery of the used paper. Similarly, below, are provided aroll 7 to pay out the fabric to be printed, for example a cotton fabric,and a roll 8 for receiving the printed fabric. The web of fabric 9leaving the payout roll 7 passes over an input roll 10, arrangedsubstantially at the level of the upper portion of drum 1, and thenenters housing 3 through an entry slot 11. It then rolls around theheating drum and passes back via slot 13 onto another guide roll 12,also outside the container, placed in the vicinity of roll 10, which theresult that the fabric is in contact with the drum over a length on theorder of three quarters of the latter's circumference. Roll 12, in theposition represented, is located at the level of the axis of the heatingdrum. In any case, it could be, constructionally, placed between anygiven level corresponding to the lower portion of the drum and the inputroll 10, which means that, in all cases, the web of fabric would remainon the heating drum 1 over at least half of its circumference.

The transfer paper 14 supplied from roll 5 passes also over an inputroll 15 placed just above roll 10 and enters the housing via a slot 11.

It is superposed upon the fabric against which it is pressed by pressingroll 2, at point A of contact with the drum. Then, it winds partiallyaround the pressing roll and exits at the upper portion of the housingvia a slot 26; it is then sent back via a guide roll 16 to the recoveryroll 6. According to an alternative form of embodiment, and to ensurethat the paper-fabric contact is not just at one point, but can takeplace over a certain portion of the drum, the transfer paper 14 returnsvia idler roll 17, as indicated in dashed lines.

The closed housing 3 is provided, at its lower portion, with air inletopenings 18 and, at its upper portion, with a discharge tube 19 fittedwith an extraction means 20 which sends the extracted air via a conduit21 into a tank 22 in which is ensured permanent water circulationbetween an inlet orifice 23 and an outlet orifice 24. The air finallyescapes from the tank via a flue 25.

Thanks to this arrangement, the vapors of the transport agent aremaintained in temperature in this state by the heating drum and, asapplicable, by pre-heating of the air entering at 18 throughout theextraction phase. This avoids any condensation or recrystallization ofthe product. The vapors in question are thus discharged by theextraction means 20 and then condense upon passing through theconstantly replenished volume of cold water in tank 22.

The winding of the printed fabric around a major part of the drum 1permits total discharge of the transport agent inside the closed housing3. The latter is completely swept by the air entering via openings 18,as well as via slots 11, 13 and 26.

FIG. 1 thus is a schematic view of the device, which can be designeddifferently, without departing from the scope of the invention, inparticular as regards discharge of the air laden with the transportagent, and the method of bubbling it through the water tank.

I claim:
 1. A device for printing on a fabric made of vegetable fibersfrom a web of transfer paper bearing coloring agents and a transportagent, comprising a heating calendering drum and a pressing roll betweenwhich a web of fabric and a web of transfer paper come into contact withone another, an independent payout roll for each of said webs, the webof printed fabric (9) remaining in contact with the heating drum (1)over at least half of its circumference, a closed housing, said heatingcalendering drum and said pressing roll (2) being received inside saidclosed housing (3), an air supply means and a tank of cold water, saidair supply means directing air to sweep through said closed housing overthe web of printed fabric, become laden with vapors and be sent intosaid tank of cold water.
 2. Printing device according to claim 1,including an input roll (10) arranged substantially at the level ofupper portion of the drum level (1) which the web of fabric passes overbefore entering the closed housing and a guide roll (12) outside theclosed housing and arranged in the vicinity of the input roll, above thelevel of the lower portion of the heating calendering drum.
 3. Printingdevice according to claims 1 or 2, including an idler roll, wherein thetransfer paper (14) remains pressed against a portion of the heatingcalendering drum (1) beyond the point at which the fabric contacts theheating calendering drum, and then passes back over said idler roll(17).
 4. Printing device according to claim 1, wherein the closedhousing (3) is provided, at its lower portion, with air inlet openings(18) and, at its upper portion, with a discharge tube (19), equippedwith an extraction means (20), emerging in the tank (22).
 5. Printingdevice according to claims 1 or 4, wherein said tank (22) has an inletorifice (23) and an outlet orifice (24) and including means topermanently supply said tank with water between said inlet orifice andsaid outlet orifice.